Technique, not size, will be the Brumbies' weapon of choice in the scrum battle against giant Chiefs props Ben Tameifuna and Jamie Mackintosh during Saturday's Super Rugby qualifying final.

The grand final rematch will be littered with head-to-head battles across Canberra Stadium, but with stats ranking the Brumbies last for winning scrums on their own feed (76 per cent), it is sure to be an area the two-time defending champions will target.

Wallabies prop Ben Alexander on Tuesday played down suggestions a neck concern that ruled him out of the international series against France would receive the ultimate test from the Chiefs' front row - whose two props weigh in at a total of 270kg.

"There's not a forward pack in this comp that doesn't test you out as a front-rower with your neck," the 62-Test Wallaby said.

"But it's 100 per cent all good."

While Alexander (120kg) and fellow Brumbies prop Scott Sio (116kg) give away 34kg to their opponents, the 29-year-old stalwart said there was more to scrummaging than size.

"Yeah, they're very big guys - you've just got to find ways around that using technique, work ethic and what-not," he said.

"Sides have scrummed well against them, and then they've touched up other sides as well."

Brumbies flanker Scott Fardy said the Brumbies would also look to limit the devastating ball-carrying impact of Tameifuna.

"He's 135kg-140kg, so we've just got to keep our tempo up on the game, make him work around the field and minimise the ability for him to get his hands on the ball," Fardy said.

With reserve Brumbies prop JP Smith ruled out for the season after suffering a knee injury during Friday's win over the Western Force, it opens the door for Australian under-20 prop Allan Alaalatoa to make his Super Rugby debut off the bench.

Director of rugby Laurie Fisher backed the 120kg youngster - who's a childhood friend of Sio's - to step up if called upon.

"Allan is not small, so I don't think he'll lack for size," Fisher said.

The Chiefs props will be backed up by outstanding All Blacks lock Brodie Retallick, who many rate as the best in the world, as well as fellow Kiwi Test back-rowers Liam Messam and Tanerau Latimer.